Raised-level built-in cooking appliance
A raised-level cooking appliance has a heating chamber with a lowerable trapdoor and a drive device. The drive device is configured to lower and lift the trapdoor. The drive mechanism is subject to a tension force, counteracting a weight of the trapdoor. The drive for moving the trapdoor may be switched off when the trapdoor comes into contact with an upper or lower stop in a simpler and more reliable manner. A control device controls the drive device in dependence on a magnitude of the tension force acting on the drive mechanism.
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This application is a continuation, under 35 U.S.C. § 120, of copending international application No. PCT/EP02/13456, filed Nov. 28, 2002, which designated the United States; this application also claims the priority, under 35 U.S.C. § 119, of German patent application No. 101 64 238.5, filed Dec. 27, 2001; the prior applications are herewith incorporated by reference in their entirety.
BACKGROUND OF THE INVENTIONField of the Invention
The present invention relates to a raised-level built-in cooking appliance, also referred to as a wall-mounted appliance, with a heating chamber, which has a floor-side chamber opening, which can be closed with a lowerable bottom door, and with a drive mechanism for lifting the bottom door, which has at least one tensile element, connected to the bottom door, which tensile element is stressed against a weight of the bottom door with a tensile force.
A wall oven described in international PCT publication WO 98/04871 is to be considered as a generic raised-level built-in cooking appliance. The wall oven has a cooking space or an oven chamber, which is enclosed by side walls, a front, back and top wall, and has a bottom oven chamber opening. The wall oven is to be attached to a wall by its rear wall in the manner of a hanging cupboard. The bottom oven chamber opening can be closed by a lowerable bottom door. The bottom door is connected to the housing via a bottom door guide mechanism. By means of the bottom door guide the bottom door can be pivoted through a lift path.
U.S. Pat. No. 2,944,540 discloses a raised-level built-in cooking appliance, in which the bottom door is connected to the cooking appliance housing via a telescopic guide mechanism. The lifting motion of the bottom door is executed by a housing-side drive motor, which is connected via pull ropes to the bottom door.
SUMMARY OF THE INVENTIONIt is accordingly an object of the invention to provide a raised-level built-in appliance, which provides improvements over the heretofore-known devices and methods of this general type and which, more particularly, provides a raised-level built-in cooking appliance in which a control for hoisting the bottom door is improved.
With the foregoing and other objects in view there is provided, in accordance with the invention, a wall-mounted cooking appliance, comprising:
- a housing defining a heating chamber and having a bottom muffle opening;
- a lowerable bottom door for selectively closing the muffle opening;
- a drive mechanism for hoisting the bottom door, the drive mechanism including at least one tensile element, connected to the bottom door and stressed against a weight of the bottom door with a given tensile force; and
- a control device connected to and controlling the drive mechanism in dependence of a magnitude of the given tensile force.
In other words, the objects are achieved with the raised-level built-in cooking appliance as described. Here, the raised-level built-in cooking appliance has at least one control device, which controls the drive mechanism in dependence on the magnitude of the tensile force occurring during a hoisting procedure. The drive mechanism can be switched on and off or the drive direction can be reversed as a result of a change in the magnitude of the tensile force.
In an advantageous embodiment of the invention the lowering procedure of the bottom door can always be terminated by means of the control device, whenever the detected tensile force falls below a specific threshold value. This is the case when the bottom door comes into contact with a working plate or another object located under the bottom door. In addition, the control device can also interrupt the bottom door drive when an upper threshold value of the tensile force is exceeded. This is the case when the bottom door comes against an upper stop, for example against the floor-side muffle opening in the cooking appliance housing.
To detect the tensile force the drive means, for example a pull rope, of the drive mechanism can be pre-tensed by a spring. With a change in the tensile force the spring moves over a spring path. Depending on the magnitude of the spring path the control device can determine the magnitude of the tensile force. Alternatively, a tensile force sensor can also be used, which detects the tensile forces engaging on a deflection sheave for the pull rope, for example.
According to a particular embodiment of the invention the control device can detect an angle of inclination of the bottom door. Depending on the magnitude of the angle of inclination the control device can drive the drive mechanism in order to reduce the angle of inclination. This angle of inclination is set when the bottom door bears on an object during a lowering procedure, for example a cooking container arranged under the bottom door. In such a case the bottom door tilts out of its normally horizontal position into a slight oblique position.
Angle sensors, which monitor the angle setting of the bottom door, can be employed to detect the angle of inclination. Alternatively, according to a preferred embodiment the magnitude of tensile forces can be detected by at least two tensile elements connected to the bottom door. Depending on a tensile force difference between the detected tensile forces the control device determines the angle of inclination of the bottom door.
The abovementioned tensile force difference can be determined for example by means of at least a first and a second switch. These switches generate switch signals when there is a change in the tensile forces in the at least two tensile elements. The control device compares corresponding switch signals of both switches and deduces the tensile force difference.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a raised-level built-in cooking device, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring now to the figures of the drawing in detail and first, particularly, to
As is evident from
The U-shaped rails 17, 21, 23 form a channel 35 according to
In
As evident from
The assembly described with reference to
In
With reference to
In
The right switch pin 99 in
The control device 103 according to the invention detects a time delay Δt between corresponding switch signals Sa1 and Sa2 and between Sbi and Sb2 of the switching elements 55a, 55b. The time delay Δt results, for example, if the bottom door comes to bear on an object as it descends, for example a cooking container arranged underneath the bottom door 9. In such a case the bottom door 9 tilts out of its normally horizontal position into a slightly oblique position. Such an oblique position of the bottom door 9 is indicated in
Unintentional pinching of human body parts is prevented by the above-mentioned detection of the angle of inclination a of the bottom door and control of the electromotor 49 depending on the size of the angle of inclination α, in particular when the bottom door 9 descends.
The electric current recorded by the electromotor 49 is detected to determine a dead-weight loading of the bottom door 9 according to the present invention, by means of the control device 103. Here the fact is employed that the current 1 recorded by the electromotor 49 behaves proportionally to a load torque, which acts on the driven shaft 57 of the electromotor 49. This connection is illustrated in a loading diagram according to
At least two lift procedures are required to detect the weight of a cooking container set on the bottom door 9. In the first lift procedure the control device 103 first detects a current value I1 for a load torque M1 as reference value. The load torque Mi is exerted on the driven shaft 57 and is necessary to raise the non-weight-loaded bottom door 9. The current value I1 is stored by the control device 103. In the subsequent second lift procedure the current value I2 is detected for a load torque M2, which is required for raising the weight-loaded bottom door 9. Depending on the magnitude of the differential values (I2-I1) the control device 103 determines the dead-weight loading of the bottom door 9.
The current requirement of the electromotor 49 is influenced by the level of the temperature in the electromotor 49. In order to compensate for this influence it is advantageous to arrange a temperature sensor 105 in the electromotor 49, as indicated in
To avoid an influence of temperature on the weight detection the dead-weight loading of the bottom door 9 can be detected according to the tensile force sensor 107 indicated in
The signal of the tensile force sensor 107 can also be used, depending on the magnitude of the tensile force, to control the electromotor 49. If the value of the tensile force measured by means of the tensile force sensor is below a lower threshold value stored in the control device 103, the electromotor 49 is then switched off. If the tensile force sensor 107 detects a value of the tensile force, which is above an upper threshold value of the tensile force, then the electromotor 49 is likewise switched off.
The tensile force sensor 105 can alternatively be replaced by a torque sensor, which detects a load torque, which is exerted on the driven shaft 57 of the electromotor 49. Piezoelectric pressure sensors or deformation or tension sensors can also be employed as sensors for measuring the dead-weight loading, for example flexible stick-on strips or materials with tension-dependent optical properties and thus cooperating optical sensors.
In the exemplary figures, the work surface 11 acts as a lower end stop for the lowered bottom door 9. Alternatively, the end stop can also be provided by selection limiters in the telescopic rails 17, 21, 23. This enables any built-in height of the raised-level built-in cooking appliance on the vertical wall 3. The maximum lift path is achieved when the telescopic parts 17, 21 and 23 are fully extended from one another and the selection limiters prevent the rails from being separated.
Claims
1. A wall-mounted cooking appliance, comprising:
- a housing defining a heating chamber and having a bottom muffle opening;
- a lowerable bottom door for selectively closing said muffle opening;
- a drive mechanism for hoisting the bottom door, said drive mechanism including at least one tensile element, connected to said bottom door and stressed against a weight of said bottom door with a given tensile force; and
- a control device connected to and controlling said drive mechanism in dependence of a magnitude of the given tensile force.
2. The cooking appliance according to claim 1, wherein said control device is configured to interrupt said drive mechanism when an upper threshold value of the tensile force is exceeded.
3. The cooking appliance according to claim 1, wherein said control device is configured to interrupt said drive mechanism when a lower threshold value of the tensile force is undershot.
4. The cooking appliance according to claim 1, which comprises a spring disposed to pre-tense said drive mechanism for detecting the tensile force, said spring moving over a spring path with a change in the tensile force, and wherein said control device is configured to determines the magnitude of the tensile force in dependence on a magnitude of the spring path.
5. The cooking appliance according to claim 4, wherein said tensile element has an end moving over the spring path and said spring is disposed to pre-tense said end moving over the spring path.
6. The cooking appliance according to claim 1, wherein said control device is configured to detect an angle of inclination of said bottom door and to control said drive mechanism to reduce the angle of inclination in dependence on a magnitude of the angle of inclination of said bottom door.
7. The cooking appliance according to claim 6, wherein said at least one tensile element is one of a first tensile element and a second tensile element stressed with first and second tensile forces, respectively, and wherein said control device is configured to detect the angle of inclination in dependence on a tensile force difference between the first and second tensile forces.
8. The cooking appliance according to claim 7, wherein said control device, for detecting the tensile force difference, includes at least a first and a second switch, generating a first and a second switch signal, respectively, by shifting said spring over the spring path, and said control device detects a time delay between generating the first and second switch signal and, depending on the magnitude of the time delay, fixes the tensile force difference.
9. The cooking appliance according to claim 8, wherein said control device is configured to reverse said drive mechanism when an upper threshold value of the time delay is undershot.
Type: Application
Filed: Jun 28, 2004
Publication Date: Jan 13, 2005
Patent Grant number: 6904905
Applicant:
Inventor: Edmund Kuttalek (Grassau)
Application Number: 10/879,790